APPARATUS AND METHOD FOR REMOVING AND RECOVERING OIL AND/OR OTHER OIL-BASED DRILLING MUD ADDITIVES FROM DRILL CUTTINGS

Method and apparatus for removing oil-based drilling mud from drill cuttings in order to prepare the drill cuttings for an environmentally safe disposal in the sea. A solvent in the range of solvents which may be condensed by ambient seawater and vaporized by heated internal combustion engine coolant is utilized in the process. The method of this invention includes the steps of transporting oil-based mud-laden cuttings to a solid feed tank wherein the oil-based cuttings are subjected to turbulent mixing to leave the surface of the cuttings substantially free of oil. The cuttings are then transported to a countercurrent flow column and subjected to countercurrent, laminar flow of solvent in order to separate oily solvent and fines smaller than a chosen diameter from the heavier solids. The heavier solids are cleaned of any remaining oil-based muds, separated from cleaning solvent and ultimately returned to the sea environment. The method includes the further step of treating the oil-based mud laden solvent for separation of remaining solvent for return of the solvent to the continuous process and for recycling of the recovered oil-based drilling mud into the drilling mud system.